Microsoft Technology Licensing, LLC

Shaun M McCarthy

Barry Thompson

Dane Snow

Stefan M Wurster

Mustansir Y Mukadam

Two transistors are connected between a power source and separate current references. The base of the first transistor is connected to a bias voltage, and the base of the second transistor is connected to the output of a differential amplifier. The amplifier inputs are connected to the nodes where the transistors are connected to the current references. The transistors and the current references may be of different sizes, such that the output voltage of the amplifier is a function of temperature and of the product of the ratios of the transistors and the current references. A number of switches may be employed such that, in alternative modes of operation, the amplifier is used to buffer the bias voltage, the offset of the amplifier, the output of the first transistor, and/or a stored sample of the temperature output voltage, which are combined to arrive at an adjusted temperature reading.

High accuracy voltage references

A transducer such as a translinear proportional-to-absolute-temperature sensor uses two amplifiers, where each amplifier is used in a variety of modes. The first amplifier generates a measurement voltage though feedback in an analog circuit. The second amplifier samples and integrates the measurement in a switched-capacitor mode, and the output is stored on a capacitor. Then the first amplifier is set to measure its offset. The offset is sampled and integrated by the second amplifier, and the output is stored on a second capacitor. Then the first and second amplifiers are set to buffer the voltages stored on the capacitors. The measurement can then be offset-adjusted by digital or analog means. The adjusted measurement is then available to be used for calibration of, e.g., an image sensor. Other transducers, such as pressure sensors, strain sensors, gyroscopes, magnetometers, accelerometers, and xyz positioning sensors may employ the same dual amplifier approach.

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Shaun M McCarthy